The secret to Alex de Minaur finally breaking through to a Grand Slam semi-final

Alex de Minaur’s horror Grand Slam quarter-final record is among the worst in history. But one subtle change in technique and mindset could propel him to the next level.

Brendan Bradford

@1bbradfo

4 min read

September 5, 2025 - 8:00AM

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The secret to Alex de Minaur finally breaking through to a maiden Grand Slam semi-final could come down to the development of one simple shot, says veteran coach and commentator, Wally Masur.

De Minaur had arguably his best chance of advancing to the final four at the US Open this week, but was knocked out by the in-form Felix Auger-Aliassime in a four-set quarter-final heartbreaker.

The 4-6 7-6 (9-7) 7-5 7-6 (7-4) loss is de Minaur’s sixth Grand Slam quarter-final defeat, including five in the last seven majors.

Only two men in the Open era have a worse record in Grand Slam quarter-finals, with Andrey Rublev losing 10 and Tommy Robredo losing seven without ever advancing to the final four.

But Masur is as confident as ever that the 26-year-old will eventually add the missing link to his game and advance to the semis.

De Minaur’s serve is letting him down. Picture: Maddie Meyer/Getty Images

And it could come down to a first serve adjustment, especially when under pressure.

“The ability to go back to a really safe, really reliable three-quarter heavy first serve, hit your spot, get a forehand and control the big points when you need it most,” Masur told Code Sports hours after de Minaur’s defeat at Flushing Meadows.

“What Demon does from the back of the court with the way he retrieves, the way he identifies when to come in, the flat ground strokes and the penetrating trajectory – there’s so many good things there.

“You can’t fault him tactically, he’s good at identifying shortfalls and putting pressure on, but that serve is one thing I would identify from the match.”

The service adjustment is related to de Minaur’s slight stature compared to many of his quarter-final opponents, including Jannik Sinner, Jack Draper and Alexander Zverev.

“He’s playing against big men, so he’s always punching above his weight, because those guys are getting easy power,” Masur said. “In the big moments, they can serve within themselves and they still get a point.

Wally Masur has known de Minaur for years. Picture: Jenny Evans/Getty Images

“He’s not getting up and over the ball and getting that big height clearance over the net, and getting that grip off the court and the heavy kick.

“He’s got a very different service. He gets pretty front on and he serves to the target, which is actually pretty old school.

“He can pop it though, and one of his fastest serves was nearly as fast as Felix’s fastest.”

Although he’s able to generate pace with his serve, the six-foot tall de Minaur has a much smaller margin of error.

“When he’s striving for power, that’s when you lose a bit of that control,” Masur said.

“You maybe get a little bit tense, you strive for pace and you don’t get your percentages right. Then you’re facing a lot of second serves and putting yourself under pressure.

“That’s what I would have identified from today. Just take a couple of bounces of the ball, hit a heavy three-quarter serve up high to the backhand, get a forehand and dictate the point.

De Minaur has four months before the Australian Open. Picture: Ishika Samant/Getty Images

“There was a breakpoint where he served a double fault, and a couple of other times where he just lacked that margin and it hurt him.”

A dejected de Minaur admitted after the match that his serve is the first thing to go when he’s under pressure.

“My serve has been letting me down in big matches,” the Aussie said. “It’s pretty tough to win a high-quality match serving the way I did today.

“It’s something that needs to improve because, if not, I’m going to put myself into a lot of trouble frequently against the top players in the later stages of these tournaments.”

Auger-Aliassime’s own safe serve proved de Minaur’s point.

The Canadian sent down 22 aces compared to de Minaur’s eight, and managed to get 64% of his first serves in compared to the Aussie’s poor 42%.

It was a shot Auger-Aliassime – who plays Sinner in the semi-final – could fall back on.

De Minaur and Auger-Aliassime embrace after their US Open quarter-final. Picture: Getty Images

“Alex had a set point in the second set at 6-5 in the tiebreak,” Masur said. “But it was on Felix’s serve and Felix just went ‘Boom’ down the centre – point over.

“To have that sort of firepower at your disposal to not go down two sets to love, that’s what the Demon’s up against.”

De Minaur has four months to address his service issues before the Australian Open, where he was knocked out in straight sets by Sinner earlier this year.

It’s enough time for any elite athlete to make adjustments, and Masur says it’s only a matter of time before he advances to a semi-final.

“I’m totally confident he will do it, and he’ll do it his way,” he said. “He’s always wanted to play aggressively, and even as a 12-year-old he could pin you to the baseline and slide it down the line.

“He’s always been pretty sure about the way he wanted to go about his business.”